Thrust controlled rotary apparatus

Abstract

The invention comprises an improved rotary apparatus comprising an outer body member having an internal generally axially directed first thrust area. An inner body member is mounted within the outer body member for relative rotation of the two body members. The inner body member has a second generally axially directed thrust area generally opposed to the first thrust area. The body members define fluid passageways and the thrust areas define a fluid-receiving space therebetween in communication with the passageways. First and second annular seals of differing diameters seal between the thrust areas, and a thrust control system is provided for selectively varying the fluid pressure in the annular portion of the fluid-receiving space bounded by the two seals by selectively providing pressure equalizing communication between that portion and a plurality of zones of differing pressures external to the annular portion.

I claim: 
     
       1. Rotary apparatus comprising: an outer body member having an internal generally axially directed first thrust area;   an inner body member mounted at least partially within said outer body member for relative rotation of said body members and having a second generally axially directed thrust area generally opposed to said first thrust area;   wherein said body members define fluid passageway means and said thrust areas define a fluid-receiving space therebetween in communication with said passageway means;   first annular seal means sealing between said thrust areas;   second annular seal means of lesser diameter than said first seal means and also sealing between said thrust areas, whereby an annular first portion of said fluid-receiving space is defined between said two seal means;   said apparatus defining two gaps located respectively an opposite sides of said first and second seal means from said first portion of said fluid-receiving space, and said gaps each communicating with a respective one of two zones of differing pressure external to said first portion;   and thrust control means for selectively varying the fluid pressure in said first portion of said fluid-receiving space, said thrust control means including means for selectively providing pressuring equalizing communication between said first portion and said two gaps.   
     
     
       2. Rotary apparatus as defined in claim 1 wherein one of said gaps comprises a second portion of said fluid-receiving space radially offset from said first portion and communicating with said fluid passageway means, and wherein said thrust control means includes means for selectively providing pressure equalizing communication between said first and second portions of said fluid-receiving space. 
     
     
       3. Rotary apparatus as defined in claim 1 wherein said first seal means is spaced radially inwardly from the radially outer extremities of said thrust areas whereby a second portion of said fluid-receiving space is defined radially outwardly of said first seal means and comprising one of said two gaps, wherein said second seal means is spaced radially outwardly from the radially inner extremities of said thrust areas whereby a third portion of said fluid-receiving space is defined radially inwardly of said second seal means and comprising the other of said two gaps, wherein said fluid passageway means includes first and second zones of differing pressures communicating with respective ones of said second and third portions of said fluid-receiving space, and wherein said thrust control means includes means for selectively providing pressure equalizing communication between said first portion and at least one of said second and third portions. 
     
     
       4. Rotary apparatus as defined in claim 3 wherein said thrust control means includes conduit means connecting said first portion and said one portion and bypassing the intermediate one of said seals; and means for selectively opening and closing said conduit means. 
     
     
       5. Rotary apparatus as defined in claim 3 wherein said thrust control means includes means for selectively providing pressure equalizing communication between said first portion and the other of said second and third portions. 
     
     
       6. Rotary apparatus as defined in claim 5 wherein said fluid passageway means includes a third zone of different pressure than either of said first and second zones, and wherein said thrust control means further includes means for selectively providing pressure equalizing communication between said third zone of said fluid passageway means and said first portion of said fluid-receiving space. 
     
     
       7. Rotary apparatus as defined in claim 6 wherein said third zone is of a pressure higher than either of said first and second zones, wherein said fluid passageway means includes a fourth zone of pressure lower than any of said first, second and third zones, and wherein said thrust control means further includes means for selectively providing pressure equalizing communciation between said fourth zone and said first portion of said fluid-receiving space. 
     
     
       8. Rotary apparatus as defined in claim 7 being a turbo-expander, said inner body member being a rotor having fluid flowway means therethrough, said flowway means including generally radially outwardly opening inlet means and generally axially opening outlet means spaced radially inwardly from said inlet means, said outer body member being a stator having inlet means and further having injection means directed into said inlet means of said rotor, and wherein said first zone of said fluid passageway means includes said injection means and communicates with said second portion of said fluid-receiving space, and said second zone of said fluid passageway means includes said outlet means of said rotor and communicates with said third portion of said fluid-receiving space. 
     
     
       9. Rotary apparatus as defined in claim 8 wherein said third zone of said fluid passageway means includes said inlet means of said stator. 
     
     
       10. Rotary apparatus as defined in claim 9 wherein said stator further comprises outlet means adjacent to and communicating with said outlet means of said rotor, and wherein said fourth zone of said fluid passageway means includes said outlet means of said stator. 
     
     
       11. Rotary apparatus as defined in claim 1 comprising means for introducing into said first portion of said fluid-receiving space, fluid of a pressure at least as high as the pressures prevailing on the other sides of said seal means from said first portion. 
     
     
       12. Rotary apparatus as defined in claim 11 wherein said fluid is introduced from a high pressure zone of said fluid passageway means. 
     
     
       13. Rotary apparatus as defined in claim 12 further comprising filter means interposed between said high pressure zone and said first portion of said fluid-receiving space. 
     
     
       14. Rotary apparatus as defined in claim 1 wherein said thrust control means is operative to selectively provide pressure equalizing communication between said first portion of said fluid-receiving space and a plurality of zones of said fluid passageway means, said zones being of differing pressures. 
     
     
       15. Rotary apparatus comprising: an outer body member having an internal generally axially directed first thrust area;   an inner body member mounted at least partially within said outer body member for relative rotation of said body members and having a second generally axially directed thrust area generally opposed to said first thrust area;   wherein said body members define fluid passageway means and said thrust areas define a fluid-receiving space therebetween in communication with said passageway means;   first annular seal means sealing between said thrust areas radially inwardly from the radially outer extremities of said thrust areas;   second annular seal means of lesser diameter than said first seal means sealing between said thrust areas radially inwardly of said first seal means but radially outwardly from the radially inner extremities of said thrust areas, whereby said fluid-receiving space is divided into co-axial inner, outer, and mid portions by said first and second seal means;   and wherein said outer body member has three bores therethrough, each of said bores communicating with a respective one of said three portions of said fluid-receiving space, whereby said apparatus may be adapted for communication of said mid portion of said fluid-receiving space with either said inner or said outer portion by interconnecting the respective ones of said bores.   
     
     
       16. The apparatus of claim 15 wherein said inner body member is a rotor having fluid flowway means therethrough, said rotor also having vent means therethrough providing communication between the said flowway means and one of said portions of said fluid-receiving space. 
     
     
       17. The apparatus of claim 16 being a turbo-expander, said flowway means of said rotor including generally radially outwardly opening inlet means and generally axially opening outlet means spaced radially inwardly from said inlet means, said vent means providing communication between said outlet means and said inner one of said portions of said fluid-receiving space. 
     
     
       18. A method of controlling thrust on a rotary apparatus of the type comprising an outer body member having an internal generally axially directed first thrust area, an inner body member mounted at least partially within said outer body member for relative rotation of said body members and having a second generally axially directed thrust area generally opposed to said first thrust area, and wherein said body members define fluid passageway means and said thrust areas define a fluid-receiving space therebetween in communication with said passageway means, comprising: providing first annular seal means sealing between said thrust areas;   providing second annular seal means of lesser diameter than said first seal means and also sealing between said thrust areas;   and selectively varying the fluid pressure in an annular first portion of said fluid-receiving space bounded by said two seal means, by selectively providing pressure equalizing communication between said first portion of said fluid-receiving space and a second portion of said fluid-receiving space, said second portion being radially offset from said first portion and in communication with said fluid passageway means.   
     
     
       19. The method of claim 18 wherein said first seal means is spaced radially inwardly from the outer extremities of said thrust area whereby said second portion of said fluid-receiving space is defined radially outwardly of said first seal means, wherein said second seal means is spaced radially outwardly from the radially inner extremities of said thrust area whereby a third portion of said fluid-receiving space is defined radially inwardly of said second seal means, wherein said fluid passageway includes first and second zones of different pressures communicating with respective ones of said second and third portions of said fluid-receiving space, and wherein said selective variation of said fluid pressure includes selectively providing pressure equalizing communication between said first portion and said third portion of said fluid-receiving space. 
     
     
       20. The method of claim 19 wherein said fluid passageway means includes a third zone of pressure higher than either of said first and second zones and a fourth zone of pressure lower than any of said first, second and third zones, and wherein said variation of fluid pressure further comprises selectively providing pressure equalizing communication between said first portion of said fluid-receiving space and said third and fourth zones. 
     
     
       21. The method of claim 20 wherein said pressure equalizing communication is provided by providing open fluid communication between said first portion of said fluid-receiving space and said first second, third and fourth zones. 
     
     
       22. The method of claim 18 wherein said pressure equalizing communication is provided by providing open fluid communication between said first and second portions of said fluid-receiving space. 
     
     
       23. The method of claim 18 comprising introducing into said first portion of said fluid-receiving space fluid of a pressure at least as high as the pressures prevailing on the other side of said seal means from said first portion. 
     
     
       24. The method of claim 23 wherein fluid is introduced from a high pressure zone of said fluid passageway means.